This invention relates to article dispensers and feeders, especially equipment for automatically feeding elongated stackable workpieces or other articles, particularly elongated articles, such as boards, having opposed planar sides in the longitudinal direction and a width across the planar sides transverse to the longitudinal direction that is at least as great as, and typically more than two times greater than, the thickness between the planar sides. These dispensers and feeders are particularly adapted for feeding such articles to a workstation or site where they will undergo assembly or other operations.
Mechanical dispensers and feeders of elongated articles are desirable, particularly for feeding workpieces to a workstation, in order to avoid the expense of additional operators for feeding the articles individually by hand. However, typical mechanical feeders are only capable of moving elongated articles individually from one location to another, without any capability for consecutive feeding to a workstation, selectively, of workpieces of differing configurations or types in a desired order or to feed elongated articles oriented with their longitudinal dimension transverse to the path of travel to a selected lateral placement at the workstation.
For some operations feeding of elongated workpieces to a precise lateral placement at a workstation is essential. Additionally, it may be a requirement that workpieces having a variety of configurations or types be fed selectively and in sequence to the workstation. A typical workstation that would benefit from such a feeding device is described in U.S. Pat. No. 5,222,290 (Patent '290), which concerns a machine for automatically applying hinges to doors and door jambs. As described in Patent '290, the jamb is placed and held in a workstation along side the side edge of the door end for application of hinges connecting the jamb and the door edge by tools mounted on carriages that move longitudinally along the jamb and door edge. It is important that a jamb of appropriate configuration be fed to the workstation for each assembly operation, and particularly a jamb configured for a left side opening door or a jamb configured for a right side opening door. It is also important that jambs be fed to the precise longitudinal location at the workstation for proper assembly with the door and that location may be different for jambs of different configuration, e.g. for a left opening or for a right opening door. Door jambs, the two side members of a door frame, will typically have a recess or notch along one longitudinal side for receiving a door edge and a notch at the top end for mating with the end edge of a horizontal sill extending between the left and right side jambs. The jamb for either a left or right-opening door is placed in the workstation with its notched longitudinal side facing in the direction of the hinge applying equipment. To place a jamb for a left-opening door in the workstation with this orientation of its notched longitudinal side, its notched top will have to be at the opposite end from that for a right-opening door placed in the workstation for this same orientation. Thus, a workstation for assembly of both left and right-opening door and frame units will need to be selectively fed door jambs configured for either left or right-side opening doors and feed them with their tops at opposite ends of the workstation. Also, the left and right-side opening jambs will need to be selectively fed to different longitudinal locations at the workstation in order to carry out the assembly operations, e.g. routing and hinge application by stationary routing and hinge-applying apparatus, at proper locations along the jambs. These positions will be different because the top of the door for a left-opening door will be at the reverse end at the workstation than that for a right-opening door. There is therefore a need for more efficient mechanical dispensing and feeding devices for elongated articles.